1. Technical Field
The present invention relates to a display device, and more particularly, to a display device using a decoder circuit which outputs voltages corresponding to digital values.
2. Related Art
As a display device of an information communication terminal, such as a computer, or of a television receiver, a liquid crystal display device has been widely used. The liquid crystal display device is a device which, by changing the orientation of liquid crystal molecules enclosed between two substrates, changes the ratio of light transmitted therethrough, and controls an image to be displayed. A decoder circuit for outputting voltages corresponding to gradation values for each pixel is mounted on a drive circuit which drives this kind of liquid crystal display device. The size of the decoder circuit is increasing accompanying an increased number of gradations in recent years, due to which an area occupied by chips increases, so a reduction in the size has been required.
JP-A-2001-34234 discloses a technology of reducing the number of gradation wires, and the size of a decoder circuit, by using a two-input amplifier which, when two input voltages are the same, carries out an output using the input voltages, and when they are different, carries out an output using a voltage intermediate between the two voltages.
With the heretofore described literature, as it is possible, by using the intermediate voltage, to reduce kinds of voltage value acting as output signals to be prepared in advance, it is possible to reduce a circuit size as a whole. However, the circuit size of a decoder portion, which selects a plurality of kinds of voltage value, prior to a stage which outputs the intermediate voltage, has not been sufficiently studied.
The invention, bearing in mind the heretofore described circumstances, has an object of providing a display device the size of a decoder circuit of which is made smaller.